Negative gauge pressure moisture management and secure adherence artificial limb system and associated methods

ABSTRACT

The negative gauge pressure moisture management and secure adherence artificial limb system is to be attached to a residual limb of an amputee. The artificial limb system includes a negative gauge pressure airflow liner, a surface area multiplying textile layer with a proximal airflow seal to surround at least a portion of the residual limb and define a regulated negative gauge pressure environment between the residual limb and the negative gauge pressure liner. The liner has a plurality of airflow passageways defining inflow air channels and an outflow air channel in fluid communication with the defined regulated negative gauge pressure environment. An airflow control system is connected inline with the outflow and inflow air channels. The airflow control system includes an airflow regulation device and an airflow initiating device.

RELATED APPLICATIONS

This application is a Continuation-in-Part (CIP) application ofcopending U.S. patent application Ser. No. 11/518,064 filed Sep. 8,2006, the entire disclosure of which is incorporated herein byreference, and which claims the benefit of U.S. Provisional ApplicationNos. 60/715,313 filed Sep. 8, 2005, 60/724,512 filed Oct. 8, 2005,60/749,942 filed Dec. 12, 2005, 60/759,327 filed Jan. 14, 2006,60/760,074 filed Jan. 18, 2006, 60/760,596 filed Jan. 21, 2006,60/777,240 filed Feb. 27, 2006, 60/798,533 filed May 8, 2006, 60/833,368filed Jul. 26, 2006, 60/837,805 filed Aug. 14, 2006, and 61/199,248filed Nov. 14, 2008 all of which are hereby incorporated herein in theirentireties by reference.

FIELD OF THE INVENTION

The present invention relates to the field of artificial limbs, and,more particularly, to liners employed in artificial limbs, relatedsystems and related methods.

BACKGROUND OF THE INVENTION

Excessive perspiration is a problem encountered by the amputeepopulation wearing an artificial limb and liner. The liner, which isdonned upon the residual limb of the amputee, for both suspension andcomfort, can be described as a non-porous elastomeric material with highthermal insulation properties nearly impermeable to moisture, forexample, as discussed in the article by Hachisuka et al. (2001) entitled“Moisture permeability of the total surface bearing prosthetic socketwith a silicone liner: is it superior to the patella-tendon bearingprosthetic socket?” J. Uoeh, 23, 225-32. An artificial limb liner sealsoff airflow to the residual limb, which results in an accumulation ofsensible and insensible perspiration between the liner and limb.

Accumulation of perspiration adversely affects limb health. Skinirritation and problems such as dermatitis and infection are clinicallyrelevant issues that have long been known to be fostered under moistconditions (e.g. see the article to Barnes (1956) entitled “Skin healthand stump hygiene”. Artif Limbs, 3, 4-19); particularly if the liner andresidual limb are not cleaned appropriately or frequently. Theaccumulated perspiration decreases the friction suspending the liner onthe residual limb. This can cause a pistoning action, which describesthe relative movement between the residual limb and liner.

Excessive limb pistoning leads to friction-related injuries and skinirritation. Examples of such problems are discussed in: Naylor, P. F.(1955) “The skin surface and friction”, Br J Dermatol, 67, 239-46;Naylor, P. F. D. (1955) “Experimental friction blisters”, Br J Dermatol,67, 327-342; and Akers et al. (1972) “The friction blister”, MilitaryMedicine, 137, 1-7. Such pistoning of the residual limb and artificiallimb liner creates the potential for catastrophic failure of thesuspension of the limb.

Amputees often complain about the accumulation of perspiration and forgood reason. While a few artificial limb users' sweat glands may reducesecretions over time, such a response is neither common nor consistentamong all users. To prevent skin problems and to maintain secureadherence, moisture accumulation is currently managed by the amputeesthemselves. They regularly remove their prosthesis to empty accumulatedmoisture and dry their limb. An artificial limb system that removesaccumulated perspiration would alleviate the conditions that make theskin more susceptible to injuries while achieving a lasting secureadherence. It might also improve their quality of life. A survey oflower limb amputees (n=90) found that perspiration inside the prosthesiswas one of the five most common reason for a reduced quality of lifeduring the summer months, as discussed in Hagberg et al. (2001)“Consequences of non-vascular trans-femoral amputation: a survey ofquality of life, prosthetic use and problems”, Prosthet Orthot Int, 25,186-94.

The current state of technology relative to moisture management in amodern artificial limb is fundamentally lacking. An artificial limbliner is donned on the amputee's stump creating an airtight seal fromwhich the artificial limb is suspended. Sensible and insensibleperspiration is trapped between the residual limb and liner in thissealed system until a build-up of moisture necessitates complete removaland “airing” of the stump.

There is a need for an approach to reduce perspiration build up in asuspension and comfort liner used in an artificial limb. The approachshould also improve secure adherence by limiting relative motion betweenthe liner and residual limb and thus mitigate pistoning.

SUMMARY OF THE INVENTION

In view of the foregoing background, it is therefore an object of thepresent invention to provide an artificial limb system and method tomanage perspiration accumulation, improve suspension and provide bothapparent and actual cooling to the residual limb of an amputee.

This and other objects, features, and advantages in accordance with thepresent invention may be provided by an negative gauge pressure moisturemanagement and secure adherence artificial limb system to be attached toa residual limb of an amputee. The system includes a negative gaugepressure airflow liner, a surface area multiplying textile layer with anairflow seal to surround at least a portion of the residual limb anddefine a regulated negative gauge pressure environment between theresidual limb and the airflow liner. The liner has a plurality ofairflow passageways defining the inflow air channels and outflow airchannel in fluid communication with the defined regulated negative gaugepressure environment. An airflow control system is connected inline withthe outflow and inflow air channels. The airflow control systemcomprises an airflow regulation device and an airflow initiating device.

The plurality of passageways of the airflow liner includes the inflowair channels in fluid communication with the regulated negative gaugepressure environment and an outflow air channel in fluid communicationwith the regulated negative gauge pressure environment. The air inflowchannels include quick detachable air inflow channel ports which arelocated on the proximal aspect of the artificial limb airflow liner.These inflow channel ports have an occlusion preventing airflow flangedesign, which comprises a plurality of airflow holes in a circularpattern, angled such that they feed distally into a central inflow airchannel and proximally into airflow grooves along the face of theflange. The air outflow channel includes a distal air outflow channelport located at the distal end of the artificial limb liner. It also hasan occlusion preventing airflow flange that has a plurality of airflowholes in a circular pattern, angled such that they feed into a centraloutflow air channel distally and proximally into airflow grooves alongthe face of the flange.

An airflow control system is connected inline with the outflow andinflow air channels. The airflow control system comprises an airflowregulation device and an airflow initiating device. An airflowregulation device may be connected at least to the outlet port, and mayinclude an electric negative gauge pressure generating device connectedto the outlet port, and an associated control circuit. An airflowinitiating device may be connected at least to the inlet port, and mayinclude an electromechanical airflow proportioning mechanism andassociated control circuit.

The airflow control system may also include a battery to power thenegative gauge pressure device with control circuit andelectromechanical airflow proportioning mechanism with control circuit,and an enclosure may contain the battery, negative gauge pressure devicewith control circuit and electromechanical airflow proportioningmechanism with associated control circuit. A radio transmitter may beincluded for activating the electromechanical airflow proportioningmechanism.

Objects, features, and advantages in accordance with the presentinvention may be provided by a negative gauge pressure moisturemanagement and secure adherence artificial limb system to be attached toa residual limb of an amputee, wherein the system includes a negativegauge pressure airflow liner, and a surface area multiplying textilelayer with an airflow seal to define a regulated negative gauge pressureenvironment between the airflow liner and the residual limb. The linerhas a plurality of airflow passageways defining the inflow air channelsand outflow air channel, in fluid communication with the regulatednegative gauge pressure environment. The air inflow channels may includequick detachable inflow channel ports which are placed in the proximalaspect of the artificial limb liner.

The inflow channel ports may have an occlusion preventing flange design,which comprises a plurality of airflow holes in a circular pattern,angled such that they feed into a central inflow air channel distallyand proximally into airflow grooves along the face of the flange. Theair outflow channel includes a outflow channel port located at thedistal end of the artificial limb liner. It also has an occlusionpreventing airflow flange that has a plurality of airflow holes in acircular pattern, angled such that they feed into a central outflow airchannel distally and proximally into airflow grooves along the face ofthe flange. An airflow control system is connected inline with theoutflow and inflow air channels. The airflow control system comprises anairflow regulation device and an airflow initiating device. The airflowregulation device is connected to the outflow channel and may include anelectric negative gauge pressure generating device and associatedcircuit controller. The airflow initiating device is connected to theinflow air channel and may include an electromechanical airflowproportioning mechanism and control circuit, which may be user activatedby radio link.

Objects, features, and advantages in accordance with the presentinvention may also be provided by a method of attaching an artificiallimb to a residual limb. The method includes providing a negative gaugepressure airflow liner, providing a surface area multiplying textilelayer with an airflow seal to surround at least a portion of theresidual limb and define a regulated negative gauge pressure environmentbetween the negative gauge pressure airflow liner and the residual limb.The liner has a plurality of airflow passageways therethrough definingthe inflow air channels and outflow air channel in fluid communicationwith the regulated negative gauge pressure environment. The methodincludes providing an airflow control system connected inline with theoutflow and inflow air channels. The airflow control system comprises anairflow regulation device and an airflow initiating device.

The liner has a plurality of airflow passageways defining the inflow airchannels and outflow air channel, in fluid communication with theregulated negative gauge pressure environment. The air inflow channelsinclude quick detachable air inflow channel ports which are placed inthe proximal aspect of the artificial limb liner. These inflow channelports have an occlusion preventing airflow flange design, whichcomprises a plurality of airflow holes in a circular pattern, angledsuch that they feed into a central inflow air channel distally andproximally into airflow grooves along the face of the flange. The airoutflow channel includes a distal air outflow channel port located atthe distal end of the artificial limb liner. It also has an occlusionpreventing airflow flange that has a plurality of airflow holes in acircular pattern, angled such that they feed into a central outflow airchannel distally and proximally into airflow grooves along the face ofthe flange.

An airflow control system is connected between the inflow and outflowchannels. The negative gauge pressure regulation device is connected tothe outflow channel and may include an electric negative gauge pressuregenerating device and circuit controller. An airflow initiating deviceis connected to the inflow air channel and may include anelectromechanical airflow proportioning mechanism with associatedcircuit controller.

The airflow control system further comprises: a battery to power theelectric negative gauge pressure generating device with circuitcontroller and electromechanical airflow proportioning mechanism withassociated controller and radio link; and a enclosure containing thebattery, electric negative gauge pressure generating device withcontroller and electromechanical airflow proportioning mechanism withcontroller and radio link.

The many embodiments of the present invention described hereincontribute to perspiration moisture management, improving suspension bylimiting pistoning between the residual limb and liner and providingboth apparent and actual cooling of the residual limb.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the surface area multiplying textile layerwith proximal airflow seal to be attached to a residual limb inaccordance with the present invention.

FIG. 2 is an anterior view of the airflow artificial limb liner to beattached to a residual limb in accordance with the present invention.

FIG. 3 is a schematic cross-sectional view of the airflow artificiallimb liner to be attached to a residual limb in accordance with thepresent invention.

FIGS. 4A-4C are schematic perspective, expanded cross-sectional andbottom views of the proximal air inflow port with its occlusionpreventing flange, a feature of the airflow artificial limb liner to beattached to a residual limb in accordance with the present invention.

FIGS. 5A-5C are schematic side, cross-sectional and perspective views ofthe distal air outflow port with an occlusion preventing flange, afeature of the airflow artificial limb liner to be attached to aresidual limb in accordance with the present invention.

FIGS. 6A and 6B are schematic cross-sectional and perspective views ofthe 4 bolt airflow lamination plate for fabrication in an artificiallimb to be attached to a residual limb in accordance with the presentinvention.

FIG. 7 is a schematic diagram of the surface area multiplying textilelayer with airflow seal, the negative gauge pressure airflow liner on aresidual limb of an amputee and airflow control system in accordancewith the present invention.

FIG. 8 is a schematic block diagram of the airflow regulation device ofthe airflow control system to be to used in accordance with the presentinvention.

FIG. 9 is a schematic view the airflow initiating device of the airflowcontrol system to be used in accordance with the present invention.

FIG. 10 is a side view of the negative gauge pressure moisturemanagement and secure adherence artificial limb system to be attached toa residual limb in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings in which preferred embodiments ofthe invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout. The dimensions of layers andregions may be exaggerated in the figures for greater clarity.

Referring initially to FIG. 1, the surface area multiplying textilelayer 1 with airflow seal 4 will now be described. A textile layer 1,which conforms snugly to the shape of an amputee's stump is laminatedwith a flexible elastomeric top 4 (e.g. silicone), of such a diameter asto conform comfortably and snugly with the proximal region of anamputee's residuum. The textile layer 1 is donned directly on theamputee's stump and worn underneath the negative gauge pressure airflowliner (described below). The textile layer 1 surrounds at least aportion of the residual limb and defines a regulated negative gaugepressure environment between negative gauge pressure airflow liner andthe residual limb. Increasing the surface area facilitatestranspiration, evaporation, and transporting moisture. The airflow seal4 of the surface area multiplying textile layer 1 includes a gentlytapered laminate transition area 2, where the fibers of the textile areadherently intertwined with silicone and terminate at the raised annularring 3. The annular ring 3 and proximal seal area 4 are devoid oftextile fibers, which effectively seals both pressure and airflow. Assuch, the airflow seal 4 is preferably an impervious seal.

An alternate embodiment of the surface area multiplying textile layer 1with airflow seal 4 may contain defined airflow passages incorporated inthe proximal seal area 4 and in fluid communication with the surfacearea multiplying textile layer. A further embodiment may includemultiple annular rings varying in shape and placement on the airflowseal 4.

Referring to FIG. 2, the negative gauge pressure airflow liner 6 will bedescribed. It is donned over the surface area multiplying textile layer1 with airflow seal 4 depicted in FIG. 1. With the application ofnegative gauge pressure, the residual limb and liner 6 are drawn intosecure adherence via the fluid communication action of the surface areamultiplying textile layer 1 with airflow seal 4. The airflow liner 6 forartificial limbs includes an elastomeric tubular body and includesproximal inflow air channels 7 and at least one distal outflow airchannel 5 (hollow locking suspension pin).

The inflow air channels 7 may further include quick detachable inflowchannel ports and associated removable air channel caps 8. Negativegauge pressure (vacuum) is commonly expressed in inches of mercury (″Hg)or millimeters of mercury (mmHg) which is equal to torr. One atmosphereequals 14.7 psia (0 psig), 29.92″Hg (0″Hg absolute), 760 mmHg, 760 torror 1,013 mbar.

An alternate embodiment of the airflow liner 6 design may have aplurality of holes in the proximal aspect of the artificial limb liner.The holes are shaped in a conical fashion with the smallest part of thecone on the inside of the liner and the largest on the outside. Theseholes cover a similar series of perforations in the proximal part of theairflow seal of the surface area multiplying textile layer and moistureis effectively transported to the surface of the artificial limb linerand away from the skin of the amputee.

Referring now to FIG. 3, a cross-section of the negative gauge pressureairflow liner 6, the air channel caps are shown as proximal quickdetachable air channel inflow ports with occlusion preventing flanges12, with sealing O-ring 11, and barb fitting 10. Also depicted is thedistal air outflow port 5 (or hollow locking pin) and includingocclusion preventing flange 9.

Referring to FIGS. 4A-4C, depicted are different views of the proximalquick detachable air inflow channel ports 8 with occlusion preventingflange 12. The air inflow channel extends through the flange 12 andports or removable channel caps 8 with sealing O-ring 11, and barbfitting 10. The bottom view (FIG. 4C) of the occlusion preventing flange12 depicts its plurality of airflow holes in a circular pattern, angledsuch that they feed into a central inflow air channel distally andproximally into airflow grooves along the face of the flange. Thisdesign prevents the surface multiplying textile layer 1 from occludingthe airflow passageways under negative gauge pressure. This design alsoprotects the skin of the amputee from localized negative gaugepressures.

An alternate embodiment for the proximal air inflow port would involve a360° annular airflow port molded in the artificial limb liner. A portencompassing 360° of equal air distribution would be advantageous inremoving moisture from the system efficiently. It would contain aplurality of airflow holes of varying sized diameters to balance airflowequally around the limb.

Referring to FIGS. 5A-5C, the distal air outflow port 5 with occlusionpreventing flange 9 will be described. The port 5 has a plurality ofairflow holes or channels 13 in a circular pattern, angled such thatthey feed into a central outflow air channel distally 14 and proximallyinto airflow grooves along the face of the flange. This design preventsthe surface multiplying textile layer 1 from occluding the airflowpassageways. This design also protects the skin of the amputee fromlocalized negative gauge pressures.

Referring to FIGS. 6A and 6B, depicted is a four-bolt airflow laminationplate 15. A pin locking mechanism is secured to the four-bolt plate anda hollow locking pin (e.g. as shown in FIG. 3) passes through thelocking mechanism and seals against the O-ring 17 retained in thefour-bolt plate 15. The outflow airflow channel exits the artificiallimb socket past a threaded section 16, to receive a barb fitting.

Referring to FIG. 7, which depicts a schematic cutaway of the surfacearea multiplying textile layer 1 with airflow seal 4 and the negativegauge pressure airflow liner 6 on a residual limb 26 of an amputee.Airflow passageways are defined by the inflow air channels 7 and outflowair channel 25 which are in fluid communication with the regulatednegative gauge pressure environment between the airflow liner 6, theresidual limb of the amputee 26, and the surface area multiplyingtextile layer 1 with proximal airflow seal 4. The inflow air channel 7and the outflow air channel 25 connect to the airflow control system 23.

The airflow control system 23 includes the negative gauge pressuregenerating device 20 and circuit controller 19 (which are describedtogether as the airflow regulation device 51, described below withreference to FIG. 8) and the key fob radio link 28 operatedelectromechanical airflow proportioning mechanism 22 and circuitcontroller 21 (which are described together as the airflow initiatingdevice 52, described below with reference to FIG. 9).

The airflow regulation device 51 creates and maintains a small pressuredifferential between the residual limb 26 and the artificial limbairflow liner 6. When the artificial limb user actuates theelectromechanical proportioning mechanism (e.g. through depressing thekey fob 28, or a pushbutton on the control circuit 21) environmental airis drawn into the airflow passageways at point 24 through the airchannels 7, through the barb fitting 10, through the quick detachableair channel ports and removable channel caps 8, with an O-ring seal 11through the proximal air inflow ports with occlusion preventing flanges12, through the surface multiplying textile layer 1, where the air isthen passed along the skin surface, facilitating moisture removal andevaporation, and on to the distal air outflow port 5 with occlusionpreventing flange 9. Air passes through air outflow port or channel 5(hollow locking pin) which is securely engaged in its locking mechanism18, and seals against the O-ring 17 retained in the four-bolt plateairflow lamination plate 15, exiting the artificial limb socket justpast a threaded section 16 which has received a barb fitting 29.

The now moisture-laden air, and if the activity level is high enough,perspiration itself, passes through outflow air channel 25, to thenegative gauge pressure generating device 20, and expelled at exit point27. This humidity reducing/perspiration removal system removes sweatwhile maintaining a secure adherence. Although a below knee residuallimb is represented in FIG. 7, this artificial limb design can be usedon above knee, below knee and upper extremity amputees, as would beappreciated by those skilled in the art.

The minimal amount of negative pressure to hold the airflow liner on isa function of the weight of the artificial limb divided by thecross-sectional area of the residual limb near the distal end. A typicaltranstibial amputee patient might require negative 5 kPa pressure (−0.75psi, −38 mm Hg) to securely hold their liner and artificial limb on. Theideal maintained negative gauge pressure setting to achieve secureadherence is about double the minimal negative gauge pressure needed tosecurely hold the limb and liner on the amputee's limb, creating asafety factor of one or unity. In the above example, a negative gaugepressure of 10 kPa would be chosen as the negative gauge pressure levelto achieve a safety factor of unity.

It should be noted that there is no increase in radial compression ofthe liner upon the residual limb because of the application of regulatednegative gauge pressure. There is, however, an increase in intimatecontact between the liner and the residual limb. It should also be notedthat the application of regulated negative gauge pressure to the insideof the airflow liner does not engender edema. Again, negative gaugepressure draws the liner and the skin into secure adherence.

The importance of negative gauge pressure inside the liner 6 is that itreduces relative motion between the residual limb and liner, andmaintains secure adherence in the presence of moisture. The applicationof negative gauge pressure inside the artificial limb liner draws theliner and the skin into secure 18 adherence. The pressure loading of theskin is transferred to the liner because relative motion has beeneliminated by the addition of regulated negative gauge pressure betweenthe stump and liner.

Creating an elevated negative gauge pressure environment between theresidual limb and liner 6 may evaporate the most energetic molecules ofperspiration on the residual limb. Adding a mass airflow mechanismaccomplished by the negative gauge pressure device removes perspirationwith increased rapidity because of the inrush of air. Negative gaugepressure, by lowering saturation vapor pressure, increases the tendencyof water to overcome its surface tension and evaporate, which is anendothermic (net heat loss) reaction. The more air pulled though theliner, the more moisture removed per unit time.

Referring to FIG. 8, depicted is the airflow regulation device 51, whichincludes the circuit controller 19 and negative gauge pressuregenerating device 20. The battery powered negative gauge pressuregenerating device 20 is connected both electronically 50 andpneumatically 49 to the circuit controller 19.

The negative gauge pressure sensor 38 is in fluid communication at port49 to the outflow air channel 25. Air and moisture is exhausted at exitpoint 27. The circuit controller 19 for the battery powered negativegauge pressure generating device 20 may include a plurality ofadjustment potentiometers 39-47 that populate this analog circuitcontroller 19. A description of their adjustment describes features ofthis circuit design.

Negative Gauge Pressure Level Adjustment 39 establishes the negativegauge pressure level setting that the negative gauge pressure generatingdevice 20 will maintain. The negative gauge pressure generating device20 will turn on at this established setting and turn off at theestablished hysteresis setting. Hysteresis adjustment 40 is adjusted ina positive direction above the negative gauge pressure level adjustment39. When hysteresis is increased, the negative gauge pressure generatingdevice stops at a higher negative gauge pressure level and the bandbetween this stopping point and the turn on point (established by thenegative gauge pressure level adjustment 39), is the dead band orhysteresis. The advantage to this configuration is that the sethysteresis amount is consistent throughout the negative gauge pressurelevel adjustment range.

Regarding motor speed adjustment 41, the negative gauge pressuregenerating device's 20 motor speed is adjustable to minimize devicenoise and conserve battery life. Depending on the negative gaugepressure level setting, the device's speed can be adjusted toefficiently maintain the desired negative gauge pressure level. Themotor speed adjustment 41 adjusts the default operating speed of thedevice.

Airflow Initiating Device Closure/Boost Threshold 42: theelectromechanical airflow proportioning mechanism 22 (e.g. FIGS. 7 and9) is closed at an established safety minimum negative gauge pressurethreshold level and a motor boost threshold is established when theairflow initiating device 52 is closed. When the electromechanicalairflow proportioning mechanism 22 is closed, the airflow InitiatingDevice Closure/Boost Threshold 42 establishes the safety boost thresholdmaintaining the set negative gauge pressure level. If the negative gaugepressure level drops below the safety threshold, the negative gaugegenerating device speed control is disabled and the device motor speedis increased in an effort to maintain minimum negative gauge pressure.If the leak is overcome by the device, and the set negative gaugepressure level is achieved, then normal device speed adjustment isre-engaged. The motor speed, however, may not be operating fast enoughto maintain the set negative gauge pressure level. In response, thespeed control is again disabled, and the device will again speed up.Speed is dependent on the size of the negative gauge pressure leak. Ifit is small, normal speed control occurs, if it is big, a faster motorspeed response occurs.

Alternate negative gauge pressure level setting 43: If theelectromechanical airflow proportioning mechanism 22 is opened to letair flow through the system, the alternate negative gauge pressure leveladjustment 43 sets the new negative gauge pressure adjustment level.When the electromechanical airflow proportioning mechanism 22 is open,the negative gauge pressure generating device speed regulation iseffectively disabled, and maximum device speed is achieved. As long asthe negative gauge pressure level is maintained above the setting of theairflow initiating device closure/Boost Threshold 42, the alternatenegative gauge pressure Level Setting 43 is in operation when theelectromechanical airflow proportioning mechanism 22 is open.

Timing Signal Adjustment 44 adjusts the length of time that a lownegative gauge pressure signal must be maintained for theelectromechanical proportioning mechanism 22 to close. Span adjustment45 allows for full scale adjustment of the negative gauge pressure leveladjustment. Negative gauge pressure sensor zero adjustment 46 adjustsfor irregularities in the manufacture of the pressure sensor 38.Threshold adjustment 47 accounts for variations in device headmanufacture and is adjusted so that the device efficiently starts andstops smoothly.

The circuit controller 19 for the negative gauge pressure generatingdevice 20 employs pulse width modulation as a power saving controldesign. Pulse width modulation in the design is independent of batteryvoltage fluctuations. The controller 19 also has a unique feature ofregenerative feedback. It is effective when the negative gauge pressuregenerator is set to run slowly. Regenerative feedback allows thenegative gauge pressure generator to adapt to the encountered headpressure. When the motor speed of the negative gauge pressure generator20 is set low, the ability of the negative gauge pressure generator toovercome head pressure is reduced and regenerative feedback prevents thesituation of togging or stalling. The advantage of regenerative feedbackis that it allows the negative gauge pressure generator to be set at alower device speed than would be possible without it, with theconcomitant noise level reduction. With regenerative feedback, as theload gets heavier, the negative gauge pressure generator 20 respondswith increased speed. The control circuit 19 of the airflow regulationdevice 51 features an analog design, the benefit of which is low powerconsumption and inherent stability and reliability of the system.

Referring to FIG. 9, the airflow initiating device 52 is depicted. Itcomprises an electromechanical airflow proportioning mechanism 22 andcircuit controller 21. The electromechanical proportioning mechanism 22is operated by key fob radio link 28 or pushbutton activation 31. Thecircuit controller 21 has a low voltage visual or audible indicator 48(e.g. a beeper) to inform the user of low battery power. The controller21 also has a low voltage closing safety feature. The electromechanicalairflow proportioning mechanism 22 is closed at a set voltage level, sothat the system will not be stuck open in the presence of batteryfailure (and no power to operate the negative gauge pressure generatingdevice). The safety signal is continuously applied, continuously drawingbattery current, locking the system closed. This allows the battery tobe completely drained and not recover, so the electromechanical airflowproportioning mechanism 22 cannot be opened until a recharged or freshbattery is installed.

Referring to FIG. 10, the negative gauge pressure moisture managementand secure adherence artificial limb system is depicted as reduced topractice on a residual limb of an amputee. The artificial limb comprisesa rigid socket 30, attachment pylon 35, tube clamps 36 and artificialfoot 37. The airflow control system 23 is attached to the pylon 35 andfits around (and obscures) the proximal tube clamp attached to the pylon35. The inflow air channel 7, with joining Y 32 and T 33 connectsdistally to the airflow initiating device housed in the airflow controlsystem 23 with a quick disconnect fitting 34. The inflow air channel 7connects proximally to the quick detachable inflow air channel ports andchannel caps 8 of the airflow liner 6, as depicted.

Pushbutton actuators 31 which open and close the electromechanicalairflow proportioning mechanism 22 are located on the circuit controlboard housed in the airflow control system 23. The outflow air channel25 connects proximally to the artificial limb socket 30 at the barbfitting 29 received by the four-bolt airflow lamination plate 15. Theoutflow air channel connects distally to the negative gauge pressuregenerating device housed in the airflow control system 23. A replaceableand/or rechargeable battery 53 powers the system.

When the electromechanical proportioning mechanism 22 is opened, animmediate pressure differential exists and air enters the system atpoint 24, which is the inlet side of an air filter connected inline withthe electromechanical proportioning mechanism of the airflow initiatingdevice. Air travels through the electromechanical proportioningmechanism 22 past the quick disconnect fitting 34, past the Y whichdivides the inlet air supply equally to the air flow channels 7supplying the medial and lateral sides of the airflow liner 6, past theT 33 which divides the air supply equally again to the anterior andposterior quick detachable inflow air channel ports and channel caps 8located on the proximal medial and proximal lateral sides of the airflowliner 6.

Air travels between the limb and airflow liner 6, through the surfaceare multiplying textile layer with airflow seal that defines thenegative gauge pressure environment between the limb and airflow liner6. Air travels over the amputee's stump, drawing away moisture, and pastthe distal air outflow channel port of the air flow liner 6, through thehollow locking suspension pin and into the four-bolt airflow laminationplate 15 of the prosthetic socket 30, moving towards the negative gaugepressure generating device housed in the airflow control system 23 viathe outflow air channel 25. The negative gauge pressure generatorfunctions to maintain secure adherence of the limb and liner creatingand maintaining the pressure differential that draws regulated air intoand through the system. Once the air passes through negative gaugepressure generator, air and moisture exhausts the system at point 27.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is to be understood that the invention is not to belimited to the specific embodiments disclosed, and that modificationsand embodiments are intended to be included within the scope of theappended claims.

1. A negative gauge pressure moisture management and secure adherenceartificial limb system to be attached to a residual limb of an amputee,the system comprising: an artificial limb airflow liner to be donnedover the residual limb; and a surface area multiplying textile layer,including a proximal airflow seal, and to surround at least a portion ofthe residual limb and define a regulated negative gauge pressureenvironment between the liner and the residual limb; the liner having aplurality of airflow passageways therethrough and defining inflow airchannels and at least one outflow air channel in fluid communicationwith the regulated negative gauge pressure environment.
 2. The negativegauge pressure moisture management and secure adherence system accordingto claim 1, wherein the artificial limb airflow liner includes quickdetachable air inflow channel ports.
 3. The negative gauge pressuremoisture management and secure adherence system according to claim 2,wherein each of the quick detachable air inflow channel ports comprisesan occlusion preventing airflow flange in fluid communication with thedefined negative gauge pressure environment between the residual limb,the surface area multiplying textile layer, and airflow liner.
 4. Thenegative gauge pressure moisture management and secure adherence systemaccording to claim 3, wherein the occlusion preventing airflow flangeincludes a plurality of airflow holes in a circular pattern and feedinginto a central inflow air channel and further into airflow grooves alonga face of the flange.
 5. The negative gauge pressure moisture managementand secure adherence system according to claim 1, wherein the artificiallimb airflow liner includes a distal air outflow channel port having anocclusion preventing airflow flange in fluid communication with thedefined negative gauge pressure environment between the residual limb,the surface area multiplying textile layer, and airflow liner.
 6. Thenegative gauge pressure moisture management and secure adherence systemaccording to claim 5, wherein the occlusion preventing airflow flange ofthe distal air outflow channel has a plurality of airflow holes in acircular pattern and feeding into a central outflow air channel andfurther into airflow grooves along a face of the flange.
 7. The negativegauge pressure moisture management and secure adherence system accordingto claim 1, further comprising an airflow control system connected tothe outflow and inflow air channels.
 8. The negative gauge pressuremoisture management and secure adherence system according to claim 7,wherein the airflow control system includes an airflow regulation deviceconnected to the outflow air channel.
 9. The negative gauge pressuremoisture management and secure adherence system according to claim 8,wherein the airflow regulation device includes an electric negativegauge pressure generating device and an associated control circuit. 10.The negative gauge pressure moisture management and secure adherencesystem according to claim 7, wherein the airflow control system furtherincludes an airflow initiating device connected to the inflow airchannels.
 11. The negative gauge pressure moisture management and secureadherence system according to claim 10, wherein the airflow initiatingdevice comprises an electromechanical airflow control proportioningmechanism and associated control circuit.
 12. The negative gaugepressure moisture management and secure adherence system according toclaim 11, wherein the airflow initiating device further includes awireless link for controlling at least the electromechanical airflowcontrol proportioning mechanism.
 13. The negative gauge pressuremoisture management and secure adherence system according to claim 7,wherein the airflow control system further comprises: a battery to powerthe electric negative gauge pressure generating device and associatedcontrol circuit, and to power the electromechanical airflowproportioning mechanism and associated control circuit; and a housingcarrying the battery, electric negative gauge pressure generating deviceand associated control circuit, and electromechanical airflowproportioning mechanism and associated control circuit.
 14. A method ofattaching an artificial limb and moisture management and secureadherence system to a residual limb, the method comprising: providing anegative gauge pressure airflow liner; providing a surface areamultiplying textile layer, including a proximal airflow seal, and tosurround at least a portion of the residual limb and define a regulatednegative gauge pressure environment between the negative gauge pressureairflow liner and the residual limb; providing the airflow liner with aplurality of airflow passageways therethrough defining inflow airchannels and at least one outflow air channel in fluid communicationwith the regulated negative gauge pressure environment; and providing anairflow control system connected inline with the outflow air channel andinflow air channels.
 15. The method according to claim 14, wherein theartificial limb airflow liner includes quick detachable air inflowchannel ports.
 16. The method according to claim 15, wherein the quickdetachable air channel ports comprise an occlusion preventing airflowflange in fluid communication with the defined negative gauge pressureenvironment between the residual limb, the surface area multiplyingtextile layer, and airflow liner.
 17. The method according to claim 16,wherein the occlusion preventing airflow flange has a plurality ofairflow holes in a circular pattern and feeding into a central inflowair channel and further into airflow grooves along a face of the flange.18. The method according to claim 17, wherein the artificial limbairflow liner includes a distal air outflow channel port with anocclusion preventing airflow flange in fluid communication with thedefined negative gauge pressure environment between the residual limband airflow liner.
 19. The method according to claim 18, wherein theocclusion preventing airflow flange of the distal air outflow channelport has a plurality of airflow holes in a circular pattern and feedinginto a central outflow air channel and further into airflow groovesalong a face of the flange.
 20. The method according to claim 14,wherein the airflow control system includes an airflow regulation deviceconnected to the outflow air channel.
 21. The method according to claim20, wherein the airflow regulation device includes an electric negativegauge pressure generating device and associated control circuit.
 22. Themethod according to claim 14, wherein the airflow control systemincludes an airflow initiating device connected to the inflow airchannels.
 23. The method according to claim 22, wherein the airflowinitiating device includes an electromechanical airflow proportioningmechanism and control circuit.
 24. The method according to claim 23,wherein the airflow initiating device further includes a wireless linkfor controlling at least the electromechanical airflow proportioningmechanism.
 25. The method according to claim 24, wherein the airflowcontrol system further comprises: a battery to power the electricnegative gauge pressure generating device and associated controlcircuit, and to power the electromechanical airflow proportioningmechanism and associated control circuit; and a housing carrying thebattery, electric negative gauge pressure generating device andassociated control circuit and electromechanical airflow proportioningmechanism and associated control circuit.